Lifting grapple



K. W. MERRYLEES LIFTING GRAPPLE Filed Nov. 12, 1941 'Oct. 6, 1942.

Patented Oct. 6, 1942 LIFTING GRAPPLE Kenneth William Merrylees, London, England Application November 12, 1941, Serial No. 418,810 In Great Britain January 16, 1941 6 Glaims.

The invention has reference to grapples for use in lifting projectiles and other articles of substantially cylindrical shape, such grapples being of the type having a yoke of more or less horseshoe formation, each limb of which carries a movable dog which is normally arranged to project across the mouth of the yoke so as to support an object enclosed therein, but which is also capable, when the grapple is lowered over an article to be lifted, of being automatically displaced outwardly until, on passing the maximum diameter of the article, it may resume its initial position by gravity. One known form of grapple of such type is provided with pivotally mounted dogs, arranged so as to be pushed upwardly and outwardly from the operative position when the yoke is passed over a projectile or the like.

The object of the present invention is the provision of an improved construction of lifting grapple of the type referred to, which will be 1 inexpensive and simple of manufacture, and which will comprise a minimum of working parts likely to sustain damage in use.

Accordingly, a grapple of the said type as characterised by the present invention, is provided with dogs which are mounted in or upon the limbs of the yoke with capability of a retractile sliding movement from the grappling position to a position in which, when the grapple is lowered over the article to be lifted, they lie clear of its maximum diameter and from which they may slide back to the grappling position by gravity.

In order that the dogs shall not project from the yoke, so as to be liable to damage when moved to the retracted position, they are preferably arranged to slide within cavities enclosed in the limbs of the yoke.

One embodiment of the invention is illustrated in and is hereinafter described with reference to the accompanying drawing, whereof Figs. 1 and 2 are a front elevation and a side elevation respectively, of one form of lifting grapple as characterised by the invention. Fig. 3 is a vertical section taken on the line IIIIII of Fig. 2.

The grapple illustrated is intended for use in raising bombs, shells and like projectiles, and it comprises a yoke which is conveniently built up from two substantially horseshoe shaped metal plates 4 disposed in relative axial alignment and rigidly spaced apart by means of an arcuate metal strip 5 to which theyare welded,

a bolt 6 connecting the plates 4 at the apex of the yoke serving for the attachment of a lifting tackle. Within a cavity enclosed between the plates 4 of each limb of the yoke there is mounted a movable dog consisting of asegmental block fitting loosely .between the plates 4. and arranged to slide along a path determined by a circumferential guide-slot 8 cut in the said spacing strip 5, a stud or projection 9 upon the block 1 passing through and co-operating with said slot 8 to guide the block and, by abutting against the ends of the slot 8, to limit its movement in either direction. Lock-nuts Ill screwing upon the projecting extremity of the stud 9 serves to retain the block I in position.

The said guide-slots 8 are of sufiicient length to permit the blocks 1 to retract slidably until they lie wholly within the spaces enclosed between the plates 4 of the yoke (as shown in Fig. 3 in full lines), and to slide downwardly, i. e. in the opposite direction, along a circular path until they enclose together a substantial portion of the open mouth of the yoke by projecting inwardly from each side thereof. This position of the blocks 1 is shown in dotted lines in Fig. 3. When the grapple is lowered over a projectile, as indicated at H, the dog-blocks l impinge against its sides and are thereby pushed upwardly within the limbs of the yoke until their innermost edges II have passed beneath the greatest diameter of the projectile, whereupon the blocks 1 automatically slide downwardly under their own weight and, at the ends of their guide-slots 8, they embrace and support portions of the undersurface of the projectile at the sides thereof. If the grapple is then raised, the blocks lock the projectile securely within the yoke in the position defined by the dotted lines in Fig. 3, holding the projectile close to or against the apex 4| of the yoke, so that it may safely be lifted and transported.

It is preferred that the sliding blocks 1 shall be so shaped, e. g. curved, on their inner faces 12 as to provide a substantial area of surface contact with the object lifted, and it will be understood that the span of the yoke will be determined by the diameter of such object.

As will be evident from the foregoing description, it is an important advantage of a lifting grapple constructed in accordance with this invention that the movable dogs I require no adjustment by hand preparatory to engagement of the grapple with the article to be lifted, since the dogs automatically fall to the operative position as soon as released after being raised by sition in which it projects partly across the mouth of the yoke and the position in which it is housed in the relative cavity.

2. A grapple for lifting cylindrical articles, comprising a yoke consisting of two horseshoeshaped plates welded along opposite edges of an arcuate metal strip, and so arranged as to enclose a cavity in each limb of the yoke, a block sliding loosely between the plates of each limb, a projection on each sliding block and a guide-slot in said strip constituting means for guiding the sliding movement of the relative block, the ends of the slot providing abutments to limit the said movement in either direction.

3. A grapple for lifting cylindrical articles, comprising a yoke consisting of two horseshoeshaped plates spaced apart in axial alignment, a bolt passing transversely through the apices of said plates, a movable dog mounted on each limb of the yoke with capability of sliding between the plates thereof from the grappling position to a position leaving the mouth of the yoke unobstructed.

4-. A grapple for lifting cylindrical articles, comprising a yoke adapted for attachment to lifting tackle and including two parallel horseshoe-shaped plates and spacing means securing said plates together, and a dog mounted on each limb of the yoke between the plates thereof for sliding movement between the grappling position in which it is rigidly supported against lateral pressure by the spacing means and a retracted position leaving the mouth of the yoke unobstructed, said dogs being maintained by gravity in the grappling position as the grapple is lowered.

5. A grapple for lifting cylindrical articles, comprising a yoke having substantially parallel limbs, and a pair of dogs mounted one within each limb of the yoke for sliding movement between a grappling position in which the dogs project inwardly into the mouth of the yoke and a retracted position in which the mouth of the yoke is unobstructed, the yoke comprising two horseshoe-shaped plates spaced apart in axial alignment so as to enclose in each limb of the yoke a cavity accommodating one of the sliding dogs, and a plate enclosing such cavity on its outward side so as to afford to the associated dog rigid lateral support in the grappling position.

6. A grapple for lifting cylindrical articles, comprising a yoke having substantially parallel limbs, and a pair of dogs mounted one within each limb of the yoke for sliding movement between a grappling position in which the dogs project inwardly into the mouth of the yoke and a retracted position in which the mouth of the yoke is unobstructed, the yoke comprising two horseshoe-shaped metal plates Welded to opposite sides of an arcuate metal strip which serves as a rigid support for the dogs when in the grappling position, and each dog being provided with a projection engaging a slot in said strip, the slot constituting a guide for the projection during the sliding movement of the dog and the ends of the slot providing abutments limiting said sliding movement in both directions.

KENNETH WILLIAM MERRYLEES. 

